Differential work-feeder for sewing machines



Dec. 3, 1936. t F. EBERT 2,063,664

DIFFERENTIAL WORK FEEDER FOR SEWING MACHINES.

Filed Feb. 26, 1954 3 Sheets-Sheet 1 8, 1936. F, EBERT DIFFERENTIAL WORK FEEDER FOR SEWING MACHINES Filed Feb. 26, 1934 3 Sheets-Sheet 2 .ZZ I/enfar:

Dec. 8, 1936. F. EBERT 2,063,664

DIFFERENTIAL WORK FEEDER FOR SEWING MACHINES .Filed Feb. 26, 1954 3 Sheets-Sheet 3 Patented Dec. 1936 UNITED STATE DIFFERENTIAL WORK-FEEDER FOB SEWING MACHINES Fritz Ebert, Oberndorf-on-the-Neckar, Germany Germany March 9, 1933 Applicationlfebruary 26, 1934, Serial No. 713,035

10 Claims.

The invention has for its object a differential work-feeder for sewing machines and is intended more particularly for high speed overcasting sewing machines.

Machines of this kind having the differential work-feeder supported independently of the main work-feeder are known but are not adapted for operation at high speeds owing to vibration resulting from their long carrierlevers which are dimcult to support adequately while performing the complicated reciprocatory movements which have to be imparted to the work-feeders.

An object of the present invention is to provide a machine of the kind in question which will be capable of operating at high speeds without objectionable vibration.

Another object of the invention is to provide means for independent adjustment of the travels of the two work-feeders.

These and other objects of the invention are achieved by the mechanisms herein claimed and exemplified in the machine illustrated in the accompanying drawings, in which:

Figs. 1 and 2 are side and rear elevations, respectively, of the differential work-feeder,

Fig. 3 is a plan view thereof,

Fig. 4 is a side elevation of the drive of the main work-feeder,

Fig. 5 is a front elevation in vertical section of the apparatus for raising the work-feeders, and

Fig. 6 is a front elevation of a guide for a workfeeder.

The horizontal main spindle 2 with driving pulley 3 is arranged in known manner in the frame I of the sewing machine. For the forward movement of the work, there is provided a differential feed which consists of the main workfeeder 4 and the differential work-feeder 5 to which varying degrees of forward movement may be given.

According to the present invention, the differential work-feeder 5 is driven from the drive of the main work-feeder 4. For this purpose, the feeder frames 6 and I of the two feeders 4 and 5 are made as double armed levers and are loosely mounted on a common spindle 8 disposed at the rear of the frame I of the sewing machine, said spindle 8 running parallel with the main spindle 2 and at approximately the same level thereof (Fig. 1). The carriers l3 and of the workfeeders 4 and 5 are mounted on the spindles II and I2 in close proximity with one another and are disposed between the upwardly directed arms 9 and ID of the feeder frames 6 and I. They tric IRQarranged on the main spindle 2 and which "is common to both carriers l3 and I4. The car- 5 riers l3, 14 are each independently supported by means of links it and I1, respectively, which embrace the eccentric l5 so that they are moved up and down on the rotation of the mainspindle 2. A body with lateral cheeks I8 is carried by a pin 10 i9 to serve as guides and said pin may be moved longitudinally, as required, by loosening a screw 20 (Fig. 3). The cheeks is, may also be easily shifted or adjusted with respect to each other in order to maintain a satisfactory guide for the 1 carriers l3 and I4. Forthis purpose, the body carrying the cheeks I3 is slit (Fig. 6) and one of said cheeks may be forced against the carriers l3 and [4 by means of a tension screw 2!.

The backward and forward movement of the m carriers l3 and I4 is derived from a common eccentric 22 arranged on the main spindle 2 and which, by means of a link 23, drives the feeder frame 6 (Fig. 4) and thus the main work-feeder 4, the feeder frame 6 on its part again driving the g5 differential work-feeder 5. The link 23 engages a downwardly projecting arm 24 having a boss 24a clamped on the boss 26 of the feeder frame 6, the boss 24a for this purpose being split and furnished with a clamping screw 24b, which en- 30 ables the arm 24 to be easily mounted and dismounted and also to be adjusted angularly and axially with respect to the feeder frame 6, as shown in Figs; 2 and 4.

The feeder frame 6 is also provided with an arm 21 projecting downwards (Fig. 1) from which is driven the feeder frame I of the differential work-feeder 5. This takes place by means of a link 28 which is connected through a ball joint 29 with a crank lever 30 which rocks about a pin 40 3| of the frame I. A further link 32 connected with a downwardly projecting arm 33 of the carrier frame I engages with the ball joint 29. When the carrier frame 6 is rocked about the axis 8, the carrier frame 1 alsosimultaneously rocked, 46 and thus the differential work-feeder 5 is moved backwards and forwards.

In order to be able to alter its feed stroke, the point 34 of the guide bar 28, by which the latter engages the arm 21 of the feeder frame 6, may 50 be shifted with respect to the axis of rotation 8, that is, be fixed at a greater or less distance therefrom. This is made possible by a curved slot 35 in which the connecting pin 34 may be moved up and down or may be fixed. The slot 35 is so made that the relative forward movement of the differential work-feeder 5 with respect to the main work-feeder 4 may be varied from 0 up to a maximum value which is determined by the proportions of the lever. In Fig. 1, there is shown in full lines the position in which the point of connection 34 is at the upper terminal position, in which position the feeder frames 6 and I and thus the work-feeders 4 and 5 both travel over the same distance with the lever proportions here chosen. In Fig. 1 is shown in dotted lines at the bottom of slot 35 the second terminal position of the connecting point 34 corresponding to the maximum forward movement of the differential work-feeder 5.

The driving movement of the feeder frame 6 can also be shifted. This is made possible by the point of attachment 36 of the link 23 to the arm 24 of the feeder frame 6 being adjustable with respect to the axis of oscillation 8. For this purpose a slot 31 is provided in the arm 24, in which the connecting pin 36 is adjustable and can be fixed. According to the adjustment of the connecting point 36, therefore, the arm 24 and with it the feeder frames 6 and I together with the work-feeders 4 and 5, carry out movements of variable amount, it being possible to again vary those of the latter with respect to one another by the adjustability of the connecting point 34.

I claim as my invention:

1. Differential work feeding mechanism for high speed overcast sewing machines, comprising a main work feeder, a differential work feeder, a carrier for each of the feeders, a pair of oscillatory levers to which the carriers are respectively jointed and each lever having an operating arm, a drive shaft, connections between the drive shaft and the operating arm of one of the oscillatory levers, a jointed link system connecting the said oscillatory lever and the operating arm of the other oscillatory lever, separate means in the said connections and link system for independently adjusting the strokes of the two arms, and means connected to the carriers close to the feeders for supporting and imparting rise and fall movements to said carriers and feeders.

2. Differential work feeding mechanism for high speed overcast sewing machines, comprising a main work feeder, a differential work feeder, a carrier for each of the feeders, a pair of oscillatory levers to which the carriers are respectively jointed and each lever having an operating arm, a drive shaft, connections between the drive shaft and the operating arm of one of the oscillatory levers, a jointed link system connecting the said oscillatory lever and the operating arm of the.

other oscillatory lever, separate means in the said connections and link system for independently adjusting the strokes of the two arms, and a single means actuated from the drive shaft for imparting rise and fall movements to both of the carriers.

3. Differential work feeding mechanism for high speed overcast sewing machines, comprising a main work feeder, a differential work feeder, a carrier for each of the feeders, a pair of oscillatory levers to which the carriers are respectively jointed and each lever having an operating arm, a drive shaft, connections between the drive shaft and the operating arm of the main work feeder carrier, means in said connections for adjusting the stroke of said carrier, a second arm on the oscillatory lever of the main carrier, a crank lever mounted on a stationary pivot in the machine, a link jointedly connecting the crank lever to said second arm by a joint adjustable relatively to the axis of said oscillatory lever, and a link connecting the crank lever to the operating arm of the oscillatory lever of the differential carrier.

4. Differential work feeding mechanism for high speed overcast sewing machines, comprising a main work feeder, a. differential work feeder, a carrier for each of the feeders, a pair of oscillatory levers to which the carriers are respeetively jointed and each lever having an operating arm, a common shaft on which said levers oscillate, a drive shaft, connections between the drive shaft and the operating arm of the main work feeder carrier, a jointed link system connecting said carrier with the operating arm of the other carrier, and separate means in the said connections and link system for independently adjusting the strokes of the two arms.

5. Differential work feeding mechanism for high speed overcast sewing machines, comprising a main work feeder, a differential work feeder, a carrier for each of the feeders, a pair of oscillatory levers to which the carriers are respectively jointed, the oscillatory lever of the main carrier having an operating arm which is axially and rotatably adjustable thereon and the oscillatory lever of the differential carrier having a non-adjustable operating arm, a common shaft on which the said levers can oscillate, a drive shaft, connections between the drive shaft and the adjustable operating arm, a jointed link system connecting the main carrier with the nonadjustable arm, and separate means in the said connections and link system for independently adjusting the strokes of the two arms.

6. Differential work feeding mechanism for high speed overcast sewing machines, comprising a main work feeder, a differential work feeder, a carrier for each of the feeders, a pair of oscillatory levers to which the carriers are respectively jointed and each lever having an operating arm, a drive shaft, connections between the drive shaft and the operating arm of one of the oscillatory levers, a jointed link system connecting the said oscillatory lever and the operating arm of the other oscillatory lever, separate means in the said connections and link system for independently adjusting the strokes of the two arms, and an eccentric actuated from the drive shaft for imparting rise and fall movements to both of the carriers, said eccentric operating separate links extending upwardly from the drive shaft to support as well as to operate the carriers.

'7. A sewing machine according to claim 6, in which the portions of the carriers near the eccentric lie side by side and are guided between jaws permitting their double oscillatory movement aforesaid.

8. A sewing machine according to claim 6, in which the portion of the carriers near the eccentric lie side by side and are guided between jaws permitting their double oscillatory movement aforesaid, said jaws being adjustable both as to their separation and transversely to the carriers.

9. A sewing machine according to claim 6, in which the portions of the carriers on the eccentric lie side by side and are guided between the arms of a U-shaped guide adjustable transversely to the carriers, one arm of the guide being flexible and adjustable by means of a set screw to vary the width of the guide.

l0. Differential work feeding mechanism for high speed overcast sewing machines comprising a main work feeder, a difierential work feeder, a pair of carrier levers arranged side by side and carrying the said feeders at their respective adjacent ends, a drive shaft, connections between the drive shaft and the other ends of the car rier levers for imparting thereto substantially horizontal reciprocatory movements, means supporting the carrier levers at their first mentioned ends' with freedom to make said movements, and a single eccentric supporting both carrier levers at their first mentioned ends and separately connected thereto by the supporting means to impart rise and fall movements to the work feeders.

FRITZ EBERT. 

